This disclosure is directed to a lamp assembly, and particularly a lamp assembly that provides energy savings. More specifically, the lamp assembly also provides for instant light and fast warm-up.
A number of different solutions currently exist to improve run-up behavior, i.e., reducing the time to full light associated with starting or igniting fluorescent lamps. By way of example only, long-life compact fluorescent lamps need approximately 0.5 to 1.5 seconds to preheat the cathodes or electrodes before starting. Before preheating is complete, there is no light emission from the lamp. Once the arc discharge is initiated, the compact fluorescent lamp (CFL) still requires an additional approximately 20 to 120 seconds or more to reach full light output.
Prior arrangements have attempted to reduce the run-up time of a CFL that uses amalgam mercury dosing by incorporating an auxiliary amalgam close to one of the electrodes in the lamp. As a result of this arrangement, mercury stored in the auxiliary amalgam is vaporized shortly after switching on. In this way, the run-up period is reduced, although this proposed solution does not provide an instant light feature.
Another proposed solution combines two lamps in one unit. More particularly, a compact fluorescent lamp and a conventional incandescent lamp are combined. Although it has been suggested to simultaneously turn on both lamps in order to result in instant light from the incandescent lamp, and then subsequently terminate or switch off the incandescent lamp, these known arrangements do not provide an efficient and effective manner for warming up the mercury source. For example, it has been suggested that a thermally sensitive element be located in the ballast compartment. This arrangement does not provide an accurate assessment of the actual thermal conditions of the discharge vessel. Further, locating a thermally sensitive element in a ballast compartment is potentially impacted by temperature variations caused by different illumination positions of the lamp e.g. vertically upright or inverted. As a result, the thermally sensitive element does not provide an accurate representation of the heat conditions.
Still another proposed solution is to apply power to the incandescent lamp only when the lamp assembly is turned on or switched on. Once a predetermined temperature is reached, the switch then de-energizes the incandescent lamp and subsequently applies power to the fluorescent lamp. Although the thermal switch associated with this arrangement aids in starting of the fluorescent lamp in low temperature, ambient conditions, it does not improve run-up of the lamp assembly.
In still another arrangement, a compact fluorescent lamp is used in conjunction with a small incandescent lamp and AC power line voltage is provided. An inverter-type ballast is combined with the lamp base and is operable to power the fluorescent lamp whenever the base is received in the associated lamp socket. A thyristor or silicon controller rectifier (SCR) causes total light provided from the combination fluorescent-incandescent lamp assembly to remain substantially constant from the moment that AC power line voltage is provided at the lamp socket. When the AC power line voltage is initially provided, light from the incandescent lamp is at its maximum, while light provided from the fluorescent lamp will be at a minimum. Thereafter, light from the incandescent lamp will gradually diminish as the fluorescent lamp gradually increases. After a period, the AC power line voltage is totally disconnected from the incandescent lamp. Unfortunately, due to the SCR, the RMS value of the input power is about 70% of the nominal and results in a specialized incandescent lamp.
Consequently, a need exists for a long-life compact fluorescent lamp that provides energy savings with instant light capabilities and fast warm-up, and overcomes the problems noted with prior proposed solutions.